Study on spectroscopic and fluorescence properties of Tb3+-doped LBTAF glasses

Absorption intensities of Tb3+ in LBTAF glasses have been analysed using the Judd–Ofelt (J–O) theory. Three J–O intensity parameters (Ω2,4,6) were calculated from the experimentally determined oscillator strengths by least square fit procedure. Reasonably small δrms±0.09×10−6 shows a good fit between experimental (fexp) and predicted (fcal) oscillator strengths. The J–O intensity parameters were then adopted to determine the spectroscopic and laser properties for the observed 5D4→7FJ (J=3–6) transitions, respectively. The luminescence intensity of these transitions increases with increase of Tb3+ concentration and no quenching effect is noticed up to 2 mol% Tb3+ ions. The decay curves show single-exponential at low concentrations (0.1 mol%) and non-exponential behaviour at higher concentrations (⩾0.5 mol%). The maximum quantum efficiency of 64% for 1.0 mol% Tb3+-doped LBTAF glass indicates its utility as laser material at 0.54 μm green wavelength.